A Study Of Power Measurement Method Of Nonlinear Load

Reasonable energy fees is based on accurate energy measurement algorithm.Traditional energy metering algorithm is facing with serious challenges, this due to the increasing non-linear loads injecting into grid, and the influence can not be ignored from harmonics and inter-harmonics. This paper study the power measurement method of nonlinear load, and committed to reducing the energy measurement error caused by harmonics and inter-harmonics, in order to achieve accurate power measurement when nonlinear load presence.Meter is a carrier of energy metering. This paper introduces the principle of induction meter and digital meter, describes the causes of its measurement error, and focuses on the presence of non-linear loads, due to the frequency range of induction meter, the phase angle error and driving elements attached measurement error and other causes.Harmonics and inter-harmonics cause continuous spectrum in electrical signal when nonlinear load presence, the traditional energy measurement algorithms based on FFT are no longer applicable. This paper a inter-harmonic analysis method based on the Fourier transform and wavelet packet transform is analyzed and compared,and proposed a new energy measurement algorithm based on wavelet packet, from energy metering or computing power point of view, this algorithm overcome measurement error caused by spectral leakage. A simulation model of the electric arc furnace is established on the Matlab/Simulink platform, the simulation results show that the energy measurement method can meet the needs when non-linear load presence.An energy measurement new algorithm based on an improved Pisarenko harmonics algorithm is proposed to overcome the Shortcoming of wavelet packet energy measurement method. Compared to traditional Pisarenko algorithm, the improved Pisarenko algorithm overcomes the shortcomings of unextracting the phase information, it can extract the parameters of the frequency components of electrical signals accurately, which can filter out spurious frequency components effectively and has a strong anti-interference ability,as a consequent,this new algorithm can meter the harmonic power separately. The proposed algorithm is verified its feasibility and effectiveness by static, dynamic tests and field measurement bysimulating the nonlinear load power signal.